Anodic oxidation of metal carbonyls in trifluoroacetic acid; stabilities of some 17-electron cations

Abstract

The electrochemical oxidation of some metal carbonyls at a Pt electrode in trifluoroacetic acid–tetrabutylammonium tetrafluoroborate (0.2 mol dm^–3) is reported. It is shown that the 17-electron cations [Cr(CO)₆]⁺, [Fe(CO)₅]⁺, [Mn(η-C₅H₅)(CO)₃]⁺ and [MnBr(CO)₅]⁺ may be prepared form their parent 18-electron carbonyls and that each has some stability in this medium. The complex [Mn₂(CO)₁₀] undergoes a two-electron oxidation and the product is [Mn(CO)₅(O₂CCF₃)]. This latter product can also be prepared by direct air oxidation.